This invention relates to compounds which are useful for retarding the growth rate of plants and in particular woody plants. Many instances exist wherein it is desirable to control the growth rate of plants and yet not destroy them. In particular, it is desirable to control the growth of plants which are in the vicinity of power lines and railroad rights-of-way.
Previous discoveries in this area include the following U.S. patents.
U.S. Pat. No. 3,627,507 discloses the use of phosphonates of Formula (a) for retarding the growth rate of woody vegetation: ##STR1## where R.sub.2 and R.sub.3 can be the same or different and each can be H, C.sub.1 -C.sub.4 alkyl, C.sub.3 -C.sub.4 alkenyl or alkynyl, or R.sub.2 and R.sub.3 can be taken together to form a ring.
U.S. Pat. No. 3,849,102 discloses the growth retardant use of the compounds of Formula (b) ##STR2## where R and R.sub.1 are alkyl or substituted alkyl and
R.sub.2 and R.sub.3 are as defined for Formula (a). PA1 R.sub.1 is methyl or ethyl; and PA1 R.sub.2 is methyl, ethyl, methoxy, or ethoxy, said methyl or ethyl groups optionally substituted with 1 to 3 chlorine atoms. PA1 a. R.sub.2 is methoxy or ethoxy; or PA1 b. R.sub.2 is methyl or ethyl, substituted with 1 to 3 chlorine atoms. PA1 1. Methyl N-(P-Hydroxy-P-methoxyphosphonocarbonyl)carbamate, sodium salt, m.p. &gt;250.degree. C PA1 2. ethyl N-(P-Hydroxy-p-ethoxyphosphonocarbonyl)carbamate sodium salt, m.p. 90.degree. -100.degree. C(dec)
British patent specification No. 1,042,208 discloses the use of compounds of Formula (c) for the preparation of lubricating compositions: ##STR3## where
R and R.sub.1 are alkyl or substituted alkyl and R.sub.2 is an acyl group, optionally substituted with one or more chlorine atoms.
Also, V. A. Shokol, B. N. Kozhushko, and A. V. Kirsanov in the Journal of General Chemistry (USSR) Vol. 43, page 547 (1973) disclose the preparation of a compound of Formula (c) where R and R.sub.1 are CH.sub.3 CH.sub.2 O-- and R.sub.2 is ##STR4## No use for this compound is disclosed.
Since there is a need for growth retarding compounds, research has continued in this area.